1000 resultados para 664.3


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The greatest threat that the biodegradable waste causes on the environment is the methane produced in landfills by the decomposition of this waste. The Landfill Directive (1999/31/EC) aims to reduce the landfilling of biodegradable waste. In Finland, 31% of biodegradable municipal waste ended up into landfills in 2012. The pressure of reducing disposing into landfills is greatly increased by the forthcoming landfill ban on biodegradable waste in Finland. There is a need to discuss the need for increasing the utilization of biodegradable waste in regional renewable energy production to utilize the waste in a way that allows the best possibilities to reduce GHG emissions. The objectives of the thesis are: (1) to find important factors affecting renewable energy recovery possibilities from biodegradable waste, (2) to determine the main factors affecting the GHG balance of biogas production system and how to improve it and (3) to find ways to define energy performance of biogas production systems and what affects it. According to the thesis, the most important factors affecting the regional renewable energy possibilities from biodegradable waste are: the amount of available feedstock, properties of feedstock, selected utilization technologies, demand of energy and material products and the economic situation of utilizing the feedstocks. The biogas production by anaerobic digestion was seen as the main technology for utilizing biodegradable waste in agriculturally dense areas. The main reason for this is that manure was seen as the main feedstock, and it can be best utilized with anaerobic digestion, which can produce renewable energy while maintaining the spreading of nutrients on arable land. Biogas plants should be located close to the heat demand that would be enough to receive the produced heat also in the summer months and located close to the agricultural area where the digestate could be utilized. Another option for biogas use is to upgrade it to biomethane, which would require a location close to the natural gas grid. The most attractive masses for biogas production are municipal and industrial biodegradable waste because of gate fees the plant receives from them can provide over 80% of the income. On the other hand, directing gate fee masses for small-scale biogas plants could make dispersed biogas production more economical. In addition, the combustion of dry agricultural waste such as straw would provide a greater energy amount than utilizing them by anaerobic digestion. The complete energy performance assessment of biogas production system requires the use of more than one system boundary. These can then be used in calculating output–input ratios of biogas production, biogas plant, biogas utilization and biogas production system, which can be used to analyze different parts of the biogas production chain. At the moment, it is difficult to compare different biogas plants since there is a wide variation of definitions for energy performance of biogas production. A more consistent way of analyzing energy performance would allow comparing biogas plants with each other and other recovery systems and finding possible locations for further improvement. Both from the GHG emission balance and energy performance point of view, the energy consumption at the biogas plant was the most significant factor. Renewable energy use to fulfil the parasitic energy demand at the plant would be the most efficient way to reduce the GHG emissions at the plant. The GHG emission reductions could be increased by upgrading biogas to biomethane and displacing natural gas or petrol use in cars when compared to biogas CHP production. The emission reductions from displacing mineral fertilizers with digestate were seen less significant, and the greater N2O emissions from spreading digestate might surpass the emission reductions from displacing mineral fertilizers.

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Con el desarrollo de las nuevas tecnologías de la comunicación, somos testigos de innovadoras formas de comportamiento en las sociedades contemporáneas que transforman la cotidianidad de los sujetos, vigente hasta hace aproximadamente tres lustros, cuando la masificación de los sistemas multimedia apenas era un ligero bosquejo de lo que hoy experimentamos. Estos cambios de comportamiento se dan a toda escala y nuestro estudio se ha dirigido a la transformación de la relación entre «ídolos deportivos y fanáticos», hoy en apariencia «más cercanos» tras las conexiones que el internet facilita. El fanático abre un nuevo espectro de relación mediática con su ídolo. Para el recuerdo quedó aquel fan cuya relación con la estrella se limitaba a coleccionar artículos, pegar posters en sus paredes y ocasionalmente poder observarlo en un escenario masivo, sea un estadio, un coliseo o una plaza pública, pero siempre a varios de metros de distancia. Otrora, la relación cara a cara, que determinaba la única forma de interacción entre el ídolo y el fan, era una odisea de verdaderos aventureros que debían atravesar fuertes circuitos de seguridad y operativos de custodia para poder conversar, o por lo menos tocar, al ídolo que tanto admiraban. Si bien en Ecuador y América Latina, en relación a Norteamérica y Europa específicamente, no existe una proliferación masificada de acceso a internet, y por ende el estudio del uso que le prestan los fanáticos a la gran red mundial apenas se ha iniciado, la fuente de donde recolectamos nuestra información es la página ‹www.ivankaviedes.com›, sitio web perteneciente al futbolista ecuatoriano Jaime Iván Kaviedes Llorentti, cuya personalidad y apariencia física han hecho de él un personaje mediático.

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The paper is devoted to the study of a type of differential systems which appear usually in the study of some Hamiltonian systems with 2 degrees of freedom. We prove the existence of infinitely many periodic orbits on each negative energy level. All these periodic orbits pass near the total collision. Finally we apply these results to study the existence of periodic orbits in the charged collinear 3–body problem.

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L'objectiu d'aquest treball és reivindicar l'autenticitat d'una inscripció ibèrica conservada al MNAT des de temps antic i condemnada sense causa justificada.

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In this work, a sol-gel route was used to prepare Y(0.9)Er(0.1)Al(3)(BO(3))(4) glassy thin films by spin-coating technique looking for the preparation and optimization of planar waveguides for integrated optics. The films were deposited on silica and silicon substrates using stable sols synthesized by the sol-gel process. Deposits with thicknesses ranging between 520 and 720 nm were prepared by a multi-layer process involving heat treatments at different temperatures from glass transition to the film crystallization and using heating rates of 2 degrees C/min. The structural characterization of the layers was performed by using grazing incidence X-ray diffraction and Raman spectroscopy as a function of the heat treatment. Microstructural evolution in terms of annealing temperatures was followed by high resolution scanning electron microscopy and atomic force microscopy. Optical transmission spectra were used to determine the refractive index and the film thicknesses through the envelope method. The optical and guiding properties of the films were studied by m-line spectroscopy. The best films were monomode with 620 nm thickness and a refractive index around 1.664 at 980 nm wavelength. They showed good waveguiding properties with high light-coupling efficiency and low propagation loss at 632.8 and 1550 nm of about 0.88 dB/cm. (C) 2009 Elsevier B.V. All rights reserved.

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International Institute of Social Research: Research-Project on Anti-Semitism" (1939-42) (veröffentlicht in Studies in Philosophy and Social Science Bd. IX, 1941, S. 124-143): 8. American Jewish Committee, Library: 1 Brief mit Unterschrift an Institute of Social Research, New York, 01.05.1941, 1 Brief mit Unterschrift von Institute of Social Research, New York, 3.5.1941, 2 Blatt; "Re: Anti-Semitism Project of the Institute of Social Research" (1941), Typoskript, 2 Blatt; "Remarks to the new form of the Project on Anti-Semitism" (27.10.1942), Typoskript, 10 Blatt; "Memorandum on a Research-Project on Anti-Semitism" (30.10.1942), a) Typoskript, 14 Blatt, b) Typoskript mit handschriftlichen Bemerkungen, 14 Blatt; Robert S. Lynd: Kommentar zu einer Beschreibung des Antisemitismus-Projekts vom 06.12.1942, Typoskript, englisch, mit handschriftlichen Korrekturen, 3 Blatt; "Outline of a Research Project on Anti-Semitism, prepared for the American Jewish Committee" (15.12.1942), a) Typoskript, 17 Blatt, b) Typoskript, 18 Blatt, c) Teilstück, Typoskript mit handschriftlichen Bemerkungen, 10 Blatt; "Memorandum on the Project on Antisemitism" (30.12.1942), a) Typoskript, 17 Blatt, b) Typoskript mit handschriftlichen Ergänzungen, 16 Blatt; "Some Methodological Errors in the Study of Antisemitism" (Januar 1943), Typoskript, 6 Blatt; "Intermediate Joint Meeting of the Institute of Social Research and the American Jewish Committee", Sitzungsprotokolle 01.03. - 27.07. 1943, Typoskripte mit handschriftlichen Korrekturen, 100 Blatt;

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The ice cover of the Arctic Ocean has been changing dramatically in the last decades and the consequences for the sea-ice associated ecosystem remain difficult to assess. Algal aggregates underneath sea ice have been described sporadically but the frequency and distribution of their occurrence is not well quantified. We used upward looking images obtained by a remotely operated vehicle (ROV) to derive estimates of ice algal aggregate biomass and to investigate their spatial distribution. During the IceArc expedition (ARK-XXVII/3) of RV Polarstern in late summer 2012, different types of algal aggregates were observed floating underneath various ice types in the Central Arctic basins. Our results show that the floe scale distribution of algal aggregates in late summer is very patchy and determined by the topography of the ice underside, with aggregates collecting in dome shaped structures and at the edges of pressure ridges. The buoyancy of the aggregates was also evident from analysis of the aggregate size distribution. Different approaches used to estimate aggregate biomass yield a wide range of results. This highlights that special care must be taken when upscaling observations and comparing results from surveys conducted using different methods or on different spatial scales.

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The euphotic depth (Zeu) is a key parameter in modelling primary production (PP) using satellite ocean colour. However, evaluations of satellite Zeu products are scarce. The objective of this paper is to investigate existing approaches and sensors to estimate Zeu from satellite and to evaluate how different Zeu products might affect the estimation of PP in the Southern Ocean (SO). Euphotic depth was derived from MODIS and SeaWiFS products of (i) surface chlorophyll-a (Zeu-Chla) and (ii) inherent optical properties (Zeu-IOP). They were compared with in situ measurements of Zeu from different regions of the SO. Both approaches and sensors are robust to retrieve Zeu, although the best results were obtained using the IOP approach and SeaWiFS data, with an average percentage of error (E) of 25.43% and mean absolute error (MAE) of 0.10 m (log scale). Nevertheless, differences in the spatial distribution of Zeu-Chla and Zeu-IOP for both sensors were found as large as 30% over specific regions. These differences were also observed in PP. On average, PP based on Zeu-Chla was 8% higher than PP based on Zeu-IOP, but it was up to 30% higher south of 60°S. Satellite phytoplankton absorption coefficients (aph) derived by the Quasi-Analytical Algorithm at different wavelengths were also validated and the results showed that MODIS aph are generally more robust than SeaWiFS. Thus, MODIS aph should be preferred in PP models based on aph in the SO. Further, we reinforce the importance of investigating the spatial differences between satellite products, which might not be detected by the validation with in situ measurements due to the insufficient amount and uneven distribution of the data.

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